


A Working Hypothesis on the Interactions Between Quirks and the Demi-Monde

by Alstromerio



Category: Rivers of London - Ben Aaronovitch, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia
Genre: Character interactions will happen later, Epistolary, Gen, If triggers warnings are needed they will go here and at the start of the chapter, Newspapers, Other Additional Tags to Be Added, Social Media, Tags May Change, Worldbuilding, an obligatory bad excuse to get characters to teach in a school, gratuitous references, gratuitous references to old bands, is happening, we're at actual dialogue now
Language: English
Status: In-Progress
Published: 2020-03-02
Updated: 2020-03-25
Packaged: 2021-02-27 20:08:18
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 2,640
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22991485
Author URL: https://archiveofourown.org/users/Alstromerio/pseuds/Alstromerio
Summary: All Might was Izuku Midoriya's third favourite hero, although he would never admit that any where Kacchan would hear. Joint first place was held by two possibly immortal policemen from England that no-one was actually sure were heroes in the first place.Actually no-one really knew what they did. Something to do with fairies?
Comments: 6
Kudos: 12





	1. Chapter 1

**Author's Note:**

> Inspired by this tumblr prompt  
> https://uncontinuous.tumblr.com/post/172095525685/so-im-still-on-my-bnha-and-rivers-of-london-kick  
> and my incessant need to explain everything to myself. God bless the internet.
> 
> If trigger warnings are necessary they will go both in the tags and at the start of every chapter in which they appear.

**It’s the Invisible Man!  
August 2020 – London ******

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London is baffled by the case of Roger Taylor, 70, who started to disappear this Thursday on the London Underground. Witnesses state that Mr. Taylor boarded the DLR Line and five minutes later “seemed to evaporate”. John Deacon who was on the DLR at the time grew concerned and tried to hold on to Mr. Taylor and was shocked to find that Mr. Taylor was still there, but invisible. During the incident Mr Taylor reportedly “glitched” several times fading in and out.

Many people are claiming the footage as a hoax, while several notable experts state that there is no evidence of tampering on the video and that there are no signs of hallucinogens in the witnesses. Mr. Taylor is unavailable for comment.

This incident joins the list of several other occurrences of individuals displaying abilities that have been though biologically impossible. The government has issued no statement at this time, although DCI Thomas Nightingale and Constable Peter Grant of the Metropolitan Police were on the scene later “as a courtesy”.

**Is this the Return to Oz?  
November 2020 – London ******

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The London Metropolitan Police was once again called to the scene of a “Quirk Incident”. Last night a distressed citizen called 911 after witnessing a green-skinned woman in Hyde Park. The citizen, who wishes to remain anonymous claimed “The sky turned green, I thought monkeys were going to start flying at me!”

The lady involved in the incident is Ana Matronic, 45. Mrs. Matronic states that she was investigating the widespread damage to the grass and that she apologises for the disruption to the police.

DCI Nightingale and Constable Grant were once again on the scene, leading some to question if the incidents are connected. Both Nightingale and Grant are members of the SAU, however neither a description of this unit’s remit, or the full title cannot be found. The police have offered no comment at this time.

**Forty Feet Remain  
January 2021 – London ******

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After attending a call last night DCI Nightingale has made a statement regarding the incident of Alex Kapranos, 47, who was pushed out a third story window. The window in question was forty foot above street level and caused quite a commotion when Mr. Kapranos hovered in the air in defiance of the laws of gravity.

DCI Nightingale clarifies that the attacker, unnamed for now, will be charged with attempted murder and that the unusual method of survival will not affect the charges. He also states that the London Metropolitan Police have no interest in any Quirk users “insofar as they follow the laws and legislations regulating everyone who enters the 32 boroughs of London in our jurisdiction”. 

Mr. Kapranos, when contacted, seemed understandably shaken after his close brush with death. He commented that he “was as surprised as anybody” when he started to float. Upon reflection he mentioned with some satisfaction that his attacker looked faint “like he was gonna fall after [me]”.

**The [Fae] Are Back In Town  
May 2021 – London ******

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Despite what the headline says, in truth they never left. This morning the Prime Minister, the Mayor of London and the Police Commissioner made a statement regarding the recent development of quirks. Recent news coverage regarding the advent of these abilities and the new legislation has been widespread, especially regarding the new legislation about quirk usage and the safety measure that have been implemented.

Concurrently the Police Commissioner revealed the existence of the “Demi-Monde”, an underground society of magic. The police and the Demi-Monde have been operating within the terms of an agreement “monitored by the Isaacs”. No information on who the Isaacs are has been revealed at this point.

The Commissioner stated that all further inquires must be addressed to DCI Thomas Nightingale and Constable Peter Grant of the SAU, although there is no information on the purview of the unit.

Metropolitan_Police _@met_police_uk _  
Quirk legislation doesn’t regulate the Demi-Monde. The Demi-Monde is regulated by the Agreement and monitored by the Isaacs.__

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Cupcake _@totalperspectivevortex  
@met_police_uk _Wait whats the agreement? Who are the isaacs?__

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Metropolitan_Police _@met_police_uk  
@totalperspectivevortex _All inquires about the Agreement are to be directed to DCI Nightingale and Constable Grant of the SAU.__

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Cupcake _@totalperspectivevortex  
@met_police_uk _Whoooo? And whats with the capital letters?__

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Snek _@murderspughurder  
@totalperspectivevortex _I think theyre the two guys who are always at the quirk incidents__

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tired _@hello_there  
@murderspughurder @totalperspectivevortex _So why are they dealing with the D-M then?? If they’re the quirk unit??__

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Snek _@murderspughurder  
@totalperspectivevortex @hello_there _Maybe they’re the go between?? To sort things out now everythings official. Going back all the cases they’re mentioned in are weird.__

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Cupcake _@totalperspectivevortex  
@murderspughurder @hello_there _shit you right. Nightingale is like super old as well, you think he has some long life quirk.__

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Snek _@murderspughurder  
@totalperspectivevortex @hello_there _only if Grant has it too, they both look damn good for their age.__

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tired _@hello_there  
@murderspughurder @totalperspectivevortex _Whose talking to Nightingale about the agreement then. Dude looks intimidating as fuck.__

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Cupcake _@totalperspectivevortex  
@murderspughurder @hello_there _Nah bro. I wouldnt start that with a tank.__

**Notes for the Chapter:**

> References:  
> The Invisible Man by Queen  
> Roger Taylor and John Deacon, the drummer and bass guitarist respectively for Queen.  
> Return to Oz by Scissor Sisters,  
> Ana Matronic, co-lead singer for Scissor Sisstors  
> 40’ by Franz Ferdinand  
> Alex Kapranos, lead singer and guitarist for Franz Ferdinand  
> The Boys Are Back In Town by Thin Lizzy
> 
> The Met Police Twitter handle has been slightly changed so that anyone searching for the real twitter handle does not come here.
> 
> Total Perspective Vortex – A concept from Hitchhikers Guide to the Galaxy. You can track the movement of every atom in existence from a single slice of cupcake  
> Hello there – A quote from a very tired General Obi-Wan Kenobi  
> murdersughurder - The snek chart from LucidCharts


	2. Chapter 2

**May 2106 ******

**Excerpt from Hero Analysis #8  
Midoriya Izuku – Age 11 ******

_Thomas Nightingale ___

Age: Unknown. 87 years since the first mention of him relating to Quirk incidents (It’s the Invisible Man article, thank you grade six history) and he looked about 40? So maybe 130? At least?

Quirk: Also unknown, but most people think it’s a long life quirk. He doesn’t look older, maybe immortality?? Is there a difference?

Profession: Detective Chief Inspector in the London Metropolitan Police. In England. Probably was the liaison for people with quirks and the police at the start? Now he works with the Demi-Monde? Fairy People? What is the SAU? What does it stand for?? What is the Demi-Monde?

Analysis: There’s no information on his quirk but he was around all the first quirk incidents in England. He’s also in charge of all questions regarding the Demi-Monde? And whatever the “Agreement” is. Why doesn’t anyone know what it is??? It’s been ninety years doesn’t anyone ask?

Allies: Peter Grant. The London Metropolitan Police. The Demi-Monde?

Additional Notes: Why’s he so scary? All the reporters look terrified when they go over to talk to him.

**Excerpt from Hero Analysis #8  
Midoriya Izuku – Age 11 ******

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_Peter Grant ___

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Age: Unknown. 130? Like Nightingale? He looked 30ish in the pictures.

Quirk: The immortality thing again? The manners??

Profession: Detective Inspector in the London Metropolitan Police.

Analysis: Why is there nothing on him?? He looks the same as in 2020? And why is everyone so polite to him? Is that a quirk? A quirk to make everyone more polite to you?

Allies: Thomas Nightingale. The London Metropolitan Police. The Demi-Monde (he’s been seen with someone who owns a river?)

**Friday 3rd January 2110 8:00AM – Two weeks before Midoriya Izuku’s UA Entrance Exam  
[A statement released by UA High School] ******

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After a long time negotiating with the London Metropolitan Police DCI Thomas Nightingale and DI Peter Grant have agreed to spend a year teaching at UA High School. They will be teaching various classes regarding the interactions between heroes and the police force, cooperation between international forces and how heroes should interact with the Demi-Monde.

DCI Nightingale and DI Grant have assured both UA and the London Metropolitan Police in the hands of their capable subordinates. Despite this should an event arise that requires their presence they will leave to handle it. These incidents will be dealt with should they occur but as a preventative measure to avoid disruption to students learning this class shall not be a requirement to graduate, although passing shall afford you a valuable qualification.

UA is incredibly lucky to be given this honour and we believe it will help mould all of our students to become better heroes in the future.

**Friday 3rd January 2110 8:10AM - Midoriya Residence ******

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“I have to get into UA! I have so many questions!”

**Monday 6th January 2110 8:49 – UA Staff Room ******

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Principal Nezu looked down at his papers. Everything was in order; had been in order the last three times he had looked, but he couldn’t stop the urge to leaf through them again. Unparalleled intelligence, perfect recall, heightened perception and he was still reduced to shuffling papers like a nervous student going into an interview for the first time.

The minute hand of the clock slowly wound its way to twelve as teachers wandered in, settling into established groups to catch up in the new year. Nemuri sauntering in towards Hizashi, both collapsing onto a couch. On the floor behind them Aizawa lay wrapped in his sleeping bag, having somehow walked in with no-one noticing.  
Five minutes before nine the door slowly opened to admit two perfectly average men. The first was dressed in a double-breasted suit and carried a folded coat and cane over one arm, the second dressed slightly more casually. Sitting on the closest unoccupied sofa together they fell into a hushed conversation, no indication from the surrounding teachers that anything was amiss.

Nezu tried to supress the urge to shuffle his papers again, struggled for a few seconds and failed.

The clock reached nine o’clock and with no overt signal the room fell silent. 

“Good morning everybody and thank you for attending the first meeting of the year. As I’m sure you all know we have a few additions to out staff.” Nezu spoke, as everyone’s eyes snapped over to the two men on the couch. “I hope everyone will ensure that they have no trouble settling in.

“Now, the first order of business is preparations for the next entrance exams. Maijima-san, how is progress on the robots?”

**Notes for the Chapter:**

> Peter does not have a quirk but he does have the talent of being a London Policeman. You will stay there and answer his questions and you will have a vague sense that you need to be More Polite Than You Are Currently Being. This is negated if the person who is being questioned is A Right Bastard
> 
> Nightingale was born in 1900 and so would turn 210 in 2110. Peter Grant is 31 in Foxglove Summer which was released in 2018, so he was born in 1987 most likely, this would make him 123.
> 
> The story is set in 2110 because BNHA takes place around three to four generations after quirks first started appearing. A generation is around 30 years long and so ninety years, or three generations, from 2020 is 2110.


	3. Chapter 3

All Might was Izuku Midoriya's third favourite hero, although he would never admit that anywhere Kacchan would hear. Joint first place was held by two possibly immortal policemen from England that no-one was sure were heroes in the first place.

Actually, no-one knew what they did. They both worked in the SAU department of the London Metropolitan Police; a department that had no full name on record, no description and before 2021 a grand total of two members. The Met categorically refused to answer any questions about them saying “it’s in the Agreement”, in the tone of a teacher who can’t admit they don’t know all the answers.

Still when he heard that they would be teaching a class at UA next year Izuku Midoriya simply redoubled his already extraordinary efforts to pass the entrance exam. All Might, concerned about the over-the-top amount of work, broke and forced Izuku to take a full twenty-four hour break.

Izuku, never one to take half measures, spent this time rereading his old hero analyses and trawling historical newspaper articles. Every other form of information on Nightingale and Grant were more like conspiracies. In fact, there were quite a few forums dedicated to theorising where they came from, what their quirks were and everything else that was unknown about DCI Nightingale and DI Grant.

According to historical records Nightingale and Grant were complete mysteries and Izuku was going to get a straight answer out of them if it killed him.

**Saturday 4th January 2110 2:15AM – The Folly  
Nineteen hours before Thomas Nightingale and Peter Grant arrive in Tokyo, Japan **

“Are you certain you remember the protocol for contacting us in an emergency?” Thomas stared slightly downwards into the eyes of Sergeant Shirley Manson, freshly promoted and temporarily in charge of an entire police department. “This is a test run to evaluate how the department runs without myself and Peter, but there are channels you can go through if you need information or resources.” 

“Yes sir.” Shirley smiled tightly. “All protocols regarding the test run are in the handbook. The department will be fine, and if it is not then there are multiple procedures in place. Enjoy your holiday.” 

“It’s a year teaching children the fine art of not pissing people off,” Peter grumbled from his place by the front door, “if it was going to be easy we wouldn’t have sensitivity seminars.” 

“A valid point Peter, however I suspect it will be more relaxing than the last four holidays. Constable Matthews is still insisting that we do not enter Canterbury Cathedral without an escort.” Thomas turned and walked to his luggage, “Now I believe the taxi is here to take us to Gatwick. It wouldn’t do for us to keep the driver waiting.” 

Walking out into the street they were greeted by a fine mist soaking the pavement and a middle-aged man looking as if the only thing keeping him vertical was habit. The edges of his mouth pulled apart slightly, creating creases in his cheeks and distorting the shape of his eyes. The expression might have been considered a smile, if the person making it considered sleep a necessity. 

Five minutes later a nondescript black cab pulled out onto the road, headlights illuminating the rain and creating a fog. 

**Saturday 4th January 2110 3:42AM – Gatwick Airport South Terminal  
Eighteen hours before Thomas Nightingale and Peter Grant arrive in Tokyo, Japan **

“This is ridiculous,” Thomas grumbled, “we’re not going to teach even the basic regulations surrounding the Demi-Monde. What good is teaching them how to act if they don’t understand why?” 

“You know that’s not why we’re actually going.” Peter returned, taking a sip of tea from a cardboard cup and grimacing. “God, that’s awful. We’re going to assess how releasing information about the Demi-Monde could affect relationships with the public now that heroism is a profession.” 

“Thank you, Peter, I had no idea. The previous year of meetings had been wiped from my memory. I just think there are better ways of starting the assessments than this.” Thomas cast a disgusted glance at Peter as he drained the cup and shuddered. “I can’t believe you drank that.” 

“We’re going to get on a sixteen-hour flight, I’m not wasting tea.” 

**Sunday 5th January 2110 6:32AM– Haneda Airport, Arrivals**

Suzuki Tarou stood in the middle of the crowd surrounding the arrivals area in the airport watching the stream of people walk through the doors, a white sign held at chest height. He raised himself up slightly to try and look over the gaggle of businessmen at the front, all looking for their escorts and adjusting their ties. A man in a grey suit and blue tie placed his briefcase on the ground to clean his glasses and a brief scuffle ensued as a man in glasses with a grey suit and green tie assumed it was his. 

The man in the blue tie was just opening the briefcase to prove his claim as two gentlemen sidestepped him to walk up to Suzuki. He swallowed as they approached, eyes flicking away to watch the contents of the briefcase spill onto the floor rather than stare. 

“DCI Nightingale and DI Grant? I’ve been assigned to take you to your hotel. Would you like some help with your luggage?” 

**Monday 6th January 2110 8:22 AM**

HeroWatchMustafa _@HW_Mustafa _  
All Might was just spotted heading towards UA! Remember he’s teaching so keep an extra eye out for villains taking advantage.__

Murder _@shewrote  
@HW_Mustafa_ DAmn I want to go back to school just to have All MIght as my teacher 

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NonNonNon _@thelittlegreycells  
@shewrote _Hell yeah! Between All Might and those two detectives anyone in UA is going to have the time of their life!__

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QuicheofDeath _@ARaisin  
@thelittlegreycells @shewrote _why ddo you want to listen to two old detectives. their not even heroes why are they teaching at UA??__

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NonNonNon _@thelittlegreycells  
@ARaisin @shewrote _Because they’re specialists in the area that they’re teaching? Which is police/hero/Demi-Monde relations? That they organised?__

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QuicheofDeath _@ARaisin  
@thelittlegreycells @shewrote _heroes dont need to work with the police. and nobody even knows what the demi mond is.__

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NonNonNon _@thelittlegreycells  
@ARaisin @shewrote _Which is…exactly…why they are teaching…__

**Notes for the Chapter:**

> Shirley Manson – Lead singer of Garbage  
> Suzuki Tarou – Main Character in Pika Ichi, a perfectly average high school student  
> Murder, She Wrote – A brilliant TV Show, staring Angela Lansbury  
> NonNonNon @thelittlegreycells – A reference to Hercule Poirot, a Belgian detective, and I bask in the glory of his genius.  
> QuicheofDeath @ARaisin - A reference to M.C. Beatons Agatha Raisin series, the first book is the Quiche of Death. It is now a TV Show as well.
> 
> From London it takes approximately one hour to get to Gatwick, at 2:00 AM I would assume minimal traffic. In England if you leave the country in the early morning it will be raining and you will get soaked, it is natural law. A flight from Gatwick to Tokyo will take around sixteen hours and Tokyo is nine hours ahead. 
> 
> Canterbury Cathedral is a masterpiece of history and architecture and everyone should visit it. For full awe-inspiring experience I suggest you watch A Knight’s Tale, starring Heath Ledger, and the visit the grave of the Black Prince.
> 
> Peter probably got tea from Starbucks. It would be terrible.


End file.
